Employee Benefit Plans (Schedule Of Information For Significant Pension Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Alaska Electrical Pension Plan [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	926005171	[1]
Plan Number	001	[1]
Year-end Date	December 31	[1]
Expiration Date of CBA's	Jun. 30, 2013	[1]
Subject to Funding Improvement Plan	No	[1]
Surcharge Paid	NA	[1]
Zone Status	Green		Green	Green
Required minimum contributions	None		None	None
Contributions (in millions)	$ 3.6		$ 3.0	$ 2.9
Contributions > 5% of total plan contributions	Yes		Yes	Yes
NRECA Retirement Security Plan [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	530116145	[1]
Plan Number	333	[1]
Year-end Date	December 31	[1]
Subject to Funding Improvement Plan	No
Surcharge Paid	NA
Zone Status	NA	[2]	NA	NA
Required minimum contributions	N/A		N/A	N/A
Contributions (in millions)	$ 3.0		$ 3.0	$ 3.1
Contributions > 5% of total plan contributions	No		No	No
Fund status	Between 65 and less than 80 percent

[1] The Alaska Electrical Pension Plan is publically available. The NRECA Retirement Security Plan is available on Chugach’s website at www.chugachelectric.com.

[2] A “zone status” determination is not required, and therefore not determined under the Pension Protection Act (PPA) of 2006. In total, the NRECA RS Plan was between 65 and less than 80 percent funded at January 1, 2012 and 2011, respectively, based on the PPA funding target and PPA actuarial value of assets on those dates.